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Патент USA US3088193

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May 7, 1963
R. L. MGILVAINE ETAL
3,088,183
APPARATUS FOR TREATING GRANULAR MATERIAL
Qriginal Filed Aug. 50, 1957
2 Sheets-Sheet 1
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m/VeA/razs
EOBE-ET L. Ma /1. l/A/A/E
0170/ ,Q/JLP/Z/ J 00/1/47
May 7, 1963
R. L. MCILVAINE ETAL
3,088,183
APPARATUS FOR TREATING GRANULAR MATERIAL
Original Filed Aug. 30, 1957
2 Sheets-Sheet 2
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United grates
1
ice
grain
Patented May 7, 1Q?3
2
of ?ow of the granular material through the apparatus
and thus the quality of the reclaimed material is positively
3,088,183
controlled and, accordingly, it is one of the principal ob—
APPARATUS FOR TREATING GRAYULAR
jects of the present invention to provide a method and
MATERIAL
Robert L. Mclivaine, Winnetka, and Ralph J. Donat, 5 apparatus for achieving this desired result.
Chicago, Ill., assignors to Herbert Simpson Corpora
It is another object of the present invention to provide
tion, Chicago, 111., a corporation of Illinois
an accurate quality control for granular material passing
Continuation of application Ser. No. 681,272, Aug. 30,
through a reclamation apparatus.
1957. This application Dec. 19, 1969, Ser. No. 76,976
A further object of the present invention is to provide
1 Claim. (CI. 22-89)
10 a new and improved method and apparatus for reclaiming
granular foundry mate-rial in which the recycling of
The present invention relates to a method and apparatus
granular material in each treating stage is individually
for treating granular material and particularly to a meth
controlled depending upon the amount of the bonding
od and apparatus for reclaiming granular materials used
coating to be removed from the granular material in each
in conventional foundry operations. Speci?cally, the pres
ent invention is an improvement of the invention disclosed 15 particular stage.
Another object of the present invention is to provide
and claimed in United States Patent No. 2,813,318 of
a multiple stage reclamation apparatus embodying an air
Walter Horth, issued November 19, 1957, and assigned
conveying, scrubbing and coating removal medium in
to the same assignee as the present invention. This ap
which
the rate of discharge of the treated material is ad—
plication is a continuation of the copending application,
coated with binder products, for example, clays, cereals,
justable from the exterior of the apparatus.
It is another object of the present invention to provide
a multiple stage reclamation apparatus embodying an air
conveying, scrubbing and coating removal medium in
which the rate of discharge of the treated material from
molded into de?nite shapes corresponding to the contours
of the castings to be made. These coatings are calcined
independently of the rate of discharge from other stages
and in which the the rates of discharge from all of the
Serial No. 681,272, ?led August 30, 1957, and assigned to
the same assignee as the present copending application.
In conventional foundry practice, granular base ma
terials, such as silica sand, zirconia sand and the like, are
resins, and oils, so that the resulting mixture can be 25 one stage to a succeeding stage is individually adjustable
or oxidized when coming into contact with molten metals
and, as a result, the base materials can only be re-used or
stages are adjustable by a common control mechanism.
in a gas stream and is projected against a target so that
removed at each stage.
It is yet another object of the present invention to pro
vide a new and improved method for reclaiming granular
Still another object of the present invention is to provide
reclaimed by removing the coatings or at least the spent 30 a new and improved multiple stage pneumatic reclamation
apparatus wherein the velocity of the pneumatic medium
portions thereof.
for scrubbing granular material is independently adjust
In the method and apparatus described in the above
able in each stage of the apparatus to provide for optimum
identi?ed application, the removal ‘of both carbonaceous
scrubbing action without pulverizing or excessive diminu
as well as non-carbonaceous coatings from the granular
tion of the granular material.
materials has been effected by the use of a so-called dry
It is another object of the present invention to provide
process employing a gas stream which functions as the
a new and improved method for reclaiming granular
sole conveying, scrubbing, and coating removal medium,
foundry material whereby the material is adapted to be
the structure for obtaining this desirable result being the
selectively recycled a predetermined number of times in
?rst commercially successful dry reclamation unit. This
each of the successive stages of the apparatus depending
structure includes a plurality of separate treating stages
upon the amount of coating of bonding material to be
within each of which the granular material is entrained
the coatings are separated from the base granular ma
terial by impact or friction and the dislodged coatings, in
the form of ?nes, are carried off by the gas stream. The
granular material is then either recycled through the
foundry material wherein a quality control is provided
for the purpose of producing reclaimed granular foundry
same treating stage or is discharged into a succeeding
material having predetermined characteristics.
tion of the coatings on the base material, the amount of
new binder products and the like which must be added in
order to render the granular material useful for further
media used to scrub the foundry material and remove the
bonding agents are individually controlled in each of the
stages so that the granular material is not pulverized or
The above and other objects are achieved, in accord
stage. In the construction shown in the prior application,
the granular material passes from treating stage to treat 50 ance with the present invention, by providing a pneumatic
reclamation apparatus of the same general type as de
ing stage through over?ow ports and the rate of ?ow
scribed in the above-identi?ed application. Briefly, the
through the stages and, hence, the quality of the reclaimed
foundry material is scrubbed or cleaned by passing it in
granular material, i.e., the amount of coating remaining
succession through a plurality of stages and in each such
on the base material after passage through all of the
stages is adjusted by controlling the rate of introduction 55 stage the material is re-scrubbed or recycled by means of
the mechanism of the present invention. This mecha
of the sand into the ?rst stage of the apparatus. How
nism includes a positive feed control for controlling simul
ever, to obtain quality and quantity control by adjusting
taneously the rates of discharge of the granular foundry
either the rate of delivery of sand to the inlet or the rate
material between successive stages in the apparatus and,
of discharge of sand from the outlet is not altogether satis
factory in all installations since the control effected is 60 hence, to control the number of recycling operations in
each stage. In order to compensate for the decreased
sluggish due to the fact that some time is required for
weight of the granular material as its bonding agents or
the sand ?ow through each stage to adjust itself to the
other coatings are removed during passage through the
change in total flow through the apparatus. In any
successive stages, discharge means at each stage are in
event, by recycling the sand through the stages a selected
number of times all or selected amounts of the coatings 65 dividually operated to change the rate of discharge from
each stage independently of the rates of discharge from
or binder products can be removed to permit subsequent
other stages. Moreover, the velocities of the pneumatic
use of the reclaimed material. By leaving a usable por
molding operations is substantially reduced.
It would be desirable to provide a method and ap
paratus for reclaiming granular material wherein the rate
70 diminuted excessively during the scrubbing operation.
Other objects and advantages of the present invention
will become apparent from the following description of an
3,088,183
4
More particularly, the sand enters each of the treating
illustrative embodiment thereof, in the course of which
reference is had to the accompanying drawings wherein:
cells 12 adjacent its upper end and moves downwardly by
gravity to be entrained in a high velocity air stream pro
duced by a blower 30, the velocity of the gas stream in
each of the treating cells ‘12 being controlled by a throttle
FIG. 1 is a diagrammatic view of a granular material
reclamation apparatus characterized by the features of the
present invention. .
valve. The throttle Valves are referred to hereinafter col
FIG. 2 is an enlarged, fragmentary, vertical, eleva
‘tional view partially in section, and illustrating certain
lectively by the reference numeral 31 and are individually
identi?ed by reference numerals 31a, 31b, 31c and 31d.
details of construction of the apparatus shown in FIG.
The air stream at the outlet vof the blower 30 passes
through a main control valve 22 to a distributing mani
fold 23 which is provided with a series of outlet pipes
1; and
FIG. 3 is an enlarged, fragmentary, perspective view
showing the details of a new and improved flow control
mechanism ‘for ‘effecting the stage-to-stage feeding.
or lines 24, 25, 26 and 27. The valve 31a is interposed
in the line 24 to control the pressure and, hence, the
Referring now to the drawings and particularly to FIG.
velocity ‘of the gas stream supplied to'the stage 112:: while
1 thereof, there is illustrated a granular material reclama
tion apparatus '10 which is particularly useful in reclaim 15 valves 31b, 31c and 31d are respectively inserted in lines
25, 2.6 and 27 to control the velocities of the air streams
ing granular materials used in foundry molding opera
in the stages 12b, 12c and 12d, respectively. While the
tions. The granular materials usually employed in these
foundry operations include, for example, silica sand, zir
valves 31a, 31]), 3-10 and 31d are illustrated as comprising
conia sand and the like and, for convenience, all such ma
adjustable pressure dropping valves, they may also corn
terials are hereinafter referred to as sand.
prise ?xed ori?ce plates for effecting predetermined pres
In conven
sure drops in the air streams passing therethrough.
In each treating cell the air stream carries the entrained
tional foundry practice, prior to use in a mold, the sand
is coated with bonding agents such as clays, cereals, resins,
cements and oils, these agents including both carbona
ce‘ous and non-carbonaceous material. The exposure of
sand upwardly through a vertical conduit or tube which
directs the combined air stream and sand against an in
the coated vsand to molten metal causes the sand to calcine 25 verted, somewhat comically shaped target.
ly prevents re-use of the sand.
The vertical
conduits in the stages 12a, 12b, 12c and 13d are designated
32a, 32b, 32c and 32d, respectively, and are generally
referred to hereinafter by reference numeral 32 while the
corresponding targets are designated as 33a, 33b, 33c
or oxidize, thereby forming a residue of spent bonding
agents as a coating on the sand particles and, unless either
completely or partially removed, each a coating e?ective
'
Additionally, the present invention contemplates the
and 33d and are generally referred to as 33. At the tar
get at least a portion of the :bonding agents or coatings
treatment of granular materials such as above enumerated
to knock off sharp projections and corners of the particles
to produce materials composed of more rounded grains.
The rounding of the grains is bene?cial in affording in
are removed ‘from the sand and are carried away as ?nes
in the air stream which is exhausted from the housing ‘11
through a gas outlet conduit 34 with the assistance of suit
creased ?owability, better packing and higher green
able suction apparatus 35. A portion of the sand pass
strengths.
ing downwardly from the target 33a, is de?ected by the
Further, it is contemplated that granular materials may
flow control mechanism .20 into :cell 1212, while a portion
of the sand from target 33b is de?ected into cell 1120
and a portion of the sand ‘from target 3250 is de?ected
into cell 12d. After treatment in all of the cells in the
manner described above, the sand is de?ected from target
33d through an outlet opening or passage 59 Where it is
collected for distribution ‘directly ‘to a molding station
be treated prior to their use in operations requiring bond
ing of the materials with liquids and powders. It has been
found that such treatment roughens the surfaces of the
grains to provide a more favorable surface for adhesion
of liquids and solid bodies than the original polished sur
faces ‘found in many granular materials prior to use.
Such treated materials when used in a molding operation
or to a storage area where it is available for future use.
provide higher green strengths and dry tensile properties
45
for given amounts of oil and bonding materials, and thus
require less of such materials, with a consequent saving
in material costs.
Brie?y, the apparatus 10 comprises a housing 11 within
which is disposed a plurality of side-by-side sand treat
'For a better understanding of the scrubbing action ef
fected in each stage reference may be had to the above
identi?ed Horth Patent No. 2,813,318. Since the treating
stages of the apparatus of the present invention are identi
cal .to one another and are similar to the treating'cells de
scribed in the Horth application, only one of these treat
ing stages, namely the stage 12a, will be described in de
»ingcells ‘or stages, these stages being referred to collec
tail.
Referring now to #FIG. 2, the treating stage 12a is dis
tively as .12 and individually as 712a, 12b, ‘12c and ‘12d
in subsequent portions of the speci?cation. Although four
posed adjacent the side wall 15 of the housing 11 and
'such stages are illustrated, it will be recognized that any
desired number can be provided with the number selected 55 includes a generally cylindrical casing or shell 42 which
for any particular installation depending upon such fac
tors as the size of the foundry, the sand handling capacity
and quality desired and other similar conditions. The
housing v11 is supported upon .a framework ‘13 so that it is
elevated somewhat with respect to the ?oor 14 of the
foundry; All ‘of the treating stages are [formed upon a
horizontal sand supporting plate or base 41 on the hous
ing 11.
'
extends downwardly from the supporting plate 41. The
conduit 32a is partially disposed within ‘the cylindrical
casing 42, thereby cooperating with the casing to de?ne
an annular passageway 29 for delivering sand from the
sand supporting plate 41 to the air stream. The'conduit
so 32!:
comprises a tube adjustably secured in the casing 42
by means [of a bracket 43 and set screw 44, the bracket
being secured to the sand supporting plate 41 by means of
bolts 45. The latter bolts may be removed to permit re
De?ned in the side wall '15 of the housing 11 and open
ing to the cell 12a is an inlet 16 for receiving sand at a 65 placement or repair of the conduit 32a and its'bracket.
The bracket 43 includes a plurality of radial ribs 43a de~
uniform and controlled rate from a vibrating feed con
?ning openings connecting the passageway 29 to the hous
ing 11 in order to permit the flow of sand downwardly
through the passageway. The casing 42 is threaded into
to the inlet 16 by other conventional feeding mechanisms
such as a screw‘conveyor or the like. In any event, with 70 an internally threaded annular ring 35 which is seated
against the underside of the plate 41 and is held in posi—
the feeding equipment illustrated the sand passes by gravity
tion by the bolts 45. The lower portion of the tube
now through the inlet 16 and then ?ows successively
32a is concentric with the casing 42 and is spaced there
through the treating cells 12a, 12b, 12c and 12d in that
' veyor :18 which in turn receives inlet sand from a storage
bin or hopper .17. Inlet sand may, of course, be supplied
order under the'control of a flow control mechanism 20
from by means of a spacer 39 suitably secured to the
characterized by the features of the present invention. 75 outside wall of the tube. The spacer 39 comprises a'cen
3,088,183
6
tral ring 39a and spaced apart ?ns 3% extending radially
up a sand mass which protects the surface of the plate
from the ring in order to de?ne openings to permit the
?ow of sand through the passageway 29. The central
ring 39a is suitably secured to the conduit 32a as, for
example, by means of set screw 37. The target 33a is
located adjacent the upper end of the tube 32a and is so
positioned that the upper end of the tube terminates sub
stantially within the con?nes of a vertical, annular lip 38,
41 and other parts within the housing 11.
In accordance with an important feature of the present
invention there is provided an improved ?ow control
mechanism 20 for positively controlling the amount of
sand ?owing from stage to stage and for also controlling
the sand flow within each stage. The mechanism 20
comprises a plurality of de?ector plates 61a, 61b, and 610
thereby to provide a restricted high velocity path for the
air stream passing outwardly between the lip 38 and the
respectively supported upon vertical partitions 64a, 64b
external surface of the tube 32a, as indicated by the ar
row pointed lines.
wall 36 of the housing 11. The partitions 64a, 64b and
and 640 and a de?ector plate 61d supported upon side
640 are mounted upon the horizontal supporting plate 41
and separate the treating stages within the housing. Thus,
partition 64a extends between the treating cells 12a and
ears 50 having aligned openings 51 therein for accom
modating a suspension cable assembly 52 which functions 15 12b, partition 64b extends between the treating cells 12b
and 120 and partition 640 extends between the treating
to suspend the target from the roof or top wall 53 of the
The target 33a includes upwardly extending lugs or
housing 11. To prevent movement of the target with re
spect to the upper end of the conduit, the target includes
a central hub 54 encircling the upper end of the conduit
cells 12c and 12d. Each de?ector plate is supported for
pivotal movement about a hinge 63. The de?ector plates
61a, 61b, 61c and 61d are so located with respect to
32 and having radially extending arms 55 secured by 20 their associated targets that a portion of the sand de?ected
from each target is intercepted and guided into the suc
ceeding or adjacent treating cell, the balance of the de
An entry piece 46 is threaded onto the lower end of the
?ected sand being returned to the sand mass on the plate
tube 32:: for the purpose of directing the air stream de
41 for recycling through the same treating cell. A pair
veloped by a curved gas inlet ?tting 47 into the tube 32a.
The ?tting 47 is connected at the outlet side of valve 31a 25 of parallel control bars 60 extending through the housing
11 and emerging from the outlet opening 59 are used in
and is secured to the lower end of the casing 42 by fasten
order to alter the positions of all of the de?ector plates
ers 43. The ?tting 47 terminates in a nozzle 48 spaced
in unison. Speci?cally, horizontal movement of the con
from the lower end of the entry piece 46 by a distance
trol bars 60 causes the de?ector plates 61a, 61b, 61c
su?icient to permit entrainment of the downwardly mov
and 61d to pivot about their hinges thus changing their
ing sand located in the passageway 29 within the upward
angular positions below their associated targets with the
ly moving air stream emitted from the nozzle. The tube
result that the rate of discharge of the treated sand from
32a is of sui?cient length to allow the sand particles en
each treating cell to the next succeeding treating cell is
trained within the air stream to reach the velocity of the
altered. By this construction, the number of recycling
air stream by the time they reach the upper end of the
tube just prior to impingement against the target 33 and, 35 operations of the sand within each treating cell may be
varied to obtain quality control since, if only a small por
to effect this result, the tube must be several feet in
tion of the treated sand is intercepted by the de?ector
length.
plates and passed to the next cell, that is, if the plates are
The construction of the nozzle 48 and the entry piece
means of bolts 57 to attaching lugs 56 on the target.
46 are such as to provide for proper entrainment of the
pivoted in a clockwise direction as viewed in FIG. 2,
substantially all of the treated sand is returned to the sand
sand in the air stream. To determine the proper degree
mass for recycling, thereby effecting more complete re
of sand entrainment, it should be observed that the scrub
moval of the coating. If, on the other hand, the de?ector
bing of the sand can best be accomplished by entraining
plates are positioned to de?ect nearly all of the sand to
su?icient sand to produce particle to particle abrasion in
the succeeding cells, that is, if the plates are pivoted in a
the target area in addition to the action produced by the
target itself and, to this end, a large volume of sand 45 counterclockwise direction as viewed in FIG. 2, very lit
tle of the sand is recycled and a lesser portion of the
should be entrained but the volume must not be enough
coating is removed, although the rate of ?ow through the
to decrease the velocity of the sand particles in the air
stages is increased.
stream since e?ective scrubbing depends upon the sand
It is frequently desirable to remove substantially all
impinging against the target at the velocity of the air
stream. As a matter of fact, it has been found that the 50 of the bonding ‘agents vand other coatings from the sand
scrubbing operation is accomplished by forming a pocket
in the ?rst few treating cells and, under these conditions,
the weight of the particles is considerably lessened. Ac
of sand at the apex of the conical target which pocket is
cordingly, it is not necessary that the sand be recycled
held in suspension by the force of the air stream and is
through the last few treating cells as many times as it is
contacted by the sand particles entrained in the air stream
recycled in the ?rst few stages. Therefore, in accordance
when these particles emerge into the target area. In addi
‘with another aspect of the present invention. the de?ector
tion, it is desirable that the amount of sand falling upon
plates are individually adjustable relative to the control
the supporting plate 41 from the target 33:: be su?icient to
bars 6% so that more of the sand may be intercepted in
provide a sand mass for receiving the particles de?ected
the ?nal treating stages to prevent unnecessary recycling
from the target, thereby preventing undue and unneces
sary erosion of the structural elements which would, in 60 of the sand after it has been substantially cleaned.
Considering now the manner in which this individual
the absence of this sand mass, be exposed to the sand
adjustment
is made, only the de?ector plate 61a and its
particles. When the apparatus 10 is not in operation,
associated structure will be described in detail, since the
material in the cylindrical casing 42 and, speci?cally, sand
de?ector plates 61b, 61c and 61d and their associated
in the passageway 29, tends to ?ow within the air inlet
structures are similar. The de?ector plate 61a comprises
?tting 47, thereby to provide an obstacle for the air stream 65 a ?at metallic plate made from material having a high
when the apparatus is started. The pressure of the gas
resistance to the abrasive action of the high velocity sand
stream from the blower 30 is generally inadequate to dis
particles. As previously mentioned, the plate 61a is pivot
place the sand located within the air inlet ?tting and, to
ally ‘attached at its lower end to a hinge 63 located at
etfect such displacement, a secondary air jet may be in 70 the upper edge of the partition 64 disposed upon the hori
troduced through a port 49 to supplement the pressure of
zontal supporting plate 41 between the cells 12a and 12b.
the main air stream passing through the ?tting 47.
The de?ector plate 61a is adapted to be moved about its
As indicated above, the sand is de?ected from the tar
hinge 63 to different angular positions below the target
get 33a toward the sand supporting plate 41 thereby com
33a independently of the movement of the other de?ector
bining with the sand ?owing through the inlet 16 to build 75 plates by means of an adjustable screw 65 threadedly se
3,088,183
8
cared to 5a bracket or support arm which is welded or
tion, the velocities of the air streams ?owing in the treat
otherwise secured to the bars 60. The plate 61a is seated
by gravity against the tip or end 65a of the adjustable
ing cells are respectively controlled by the throttle valves
31a, 31b, 31c and 31d. When'the de?ector plates 61a,
screw 65 and, as a result, the screw may be turned in a
direction to move its tip 65a toward the right as viewed
61b, 61c and 61d are differently arranged relative to the
bars 68 in the manner indicated above, it is important "that V
the lighter weight sand in the .?nal treating stages does
not impinge against the respective targets with the same
velocity that the sand impinges against the target 33a in
the ?rst treating cell 120. In order to prevent the light
to pivot in a counterclockwise direction to de?ect more 10 weight sand from being pulverized or over-cleansed in
the ?nal treating cells, the throttle control valves are ad
sand from the target to the cell 12b.
justed to reduce the air stream "elocities in these particu
Suitable locking nuts (not shown) may be used to hold
lar cells. Thus, in the ?rst treating cell i12a where the
the screw 65 in position on the bracket 66 after the screw
sand is heavily coated with a bonding agent, the velocity
has been adjusted. Rotation of de?ector plates in a
of the air stream is relatively high, whereas in the ?nal
clockwise direction as viewed in FIG. 2 is limited by the
treating cells 12c and 12d where the sand is compara
sections of the hinge '63 which effectively prevent the de
tively clean and there is little cushioning effect from the
?ector plates from moving beyond a vertical position.
bonding agent, the air stream velocities are progressively
Rotation of the de?ector plates in a counterclockwise di
reduced with the result that pulverizing or excessive
rection is limited by the arms or brackets 66 in the event
a that the adjusting screw is moved toward the left and 20 diminution of the sand particles is avoided.
The ?ow control mechanism of the present invention
beyond the limiting position.
effects a stage—to-stage sand ?ow while permitting the
As previously indicated, the remaining de?ector plates
stages to be located at the same elevation. In this man
61b, 61c and 61d are also individually adjustable rela
ner, the overhead space required for the installation is
tive to the controllba-rs 60 so that they can be pivoted
about their hinge pins to different angular positions. 25 minimized, a factor which is extremely important in small
foundries where the available overhead is limited. More
Moreover, while the de?ector plates 61a, 61b, 61c and
over, if desired, the successive treating cells could be
61d ‘are independently pivctable by means of the adjust
progressively elevated somewhat by using the de?ectors
ing screws 65 all of these de?ector plates may be simul
in the ?ow control mechanism of the present invention
taneously pivoted by horizontal movement of the common
30 to e?ect interstage feeding.
control-bars 60 as described above.
in FIG. 2, thereby pivoting the plate 61a in a clockwise
direction and de?ecting less of the sand to the cell 1212,
or, alternatively, the screw 65 may be selectively turned
to move its tip to the left, thus allowing the plate 61a
While the present invention has been described in con
nection with an illustrative embodiment thereof, it should
be understood that many modi?cations will be apparent
one of the bars 60 can be eliminated. In any event the
to those skilled in the art and it is therefore intended in
framework or, more speci?cally, the bars 60 are supported
and moved by a suitable manually operable mechanism 35 the appended claims to cover all such modi?cations fall~
\In installations where a single control bar is sufficient
to support the sand load falling upon the de?ector plates,
68, shown only in FIG. 1, which is capable of moving
the bars 60 horizontally along guide rails 69 supported
ing within the true spirit and scope of the invention.
upon structure 70 secured either to theplate 41 or to the
What is claimed as new and is desired to be secured by
Letters Patent of the United States is:
walls'of the housing 11. As indicated above, movement
A granular material treating apparatus comprising a
the targets to be recycled through the treating cells. In
able directing members respectively disposed between
of the control bars 66 horizontally to the left as viewed 4-0 plurality of target means, a plurality of side-by-side tr'eat
ing cells in each of which granular material is entrained
in FIG. 2 causes the de?ector plates 61a, 61b, 61c and
within a gas stream directed against one of said target
61d to be pivoted simultaneously in a counterclockwise
means for removing portions of the outer surface of
direction in order to intercept an increased quantity of
the granular material so that the remainder of the granu
the sand de?ected from the targets 33. Conversely, when
45
lar material after removal of the surface portions is de
the control bars 60 ‘are moved to the right, the de?ector
?ected by the target means toward a collecting point for
plates 61a, 61b, 61c and 61d intercept a smaller amount
recycling through the gas stream, a plurality ‘of adjust
of sand, thereby causing more of the sand de?ected from
this manner, an e?ective, accurate control of the quality 50 each target means and ‘its associated collecting point for
of the sand emanating from the discharge opening 59 is
intercepting a portion of the material de?ected by each
target and feeding it to the succeeding stage in order to
effect stage~to~stage flow of the granular material, means
' for individually and independently ‘adjusting each direct
trolling the degree of recycling of the sand during a pre
determined time period.
55 ing member in ‘order to vary the amount of material inter
cepted in each stage, thereby to control the recycling, and
-In operation, it has been found advisable to position
means for adjusting the position of all of the directing
the plate 61a so that only a relatively small amount of
members in unison in order to vary the rate of ?ow of
sand is discharged from treating cell 12a to the cell 12b,
granular material through the stages.
whereby'the sand Within the cell 12a is recycled a large
obtained since a positive and controlled sand flow is pro
vided between successive stages for the purpose of con
number of times to remove a considerable amount of the 60
a bonding agents coated on the sand prior to passage of the
sand into the succeeding treating cells 12b, \12c and 12d.
Since the sand becomesprogressively cleaner in treating
cells 12b, 12c and 12d it need be recycled a fewer num
ber of times in each successive stage and, accordingly, 65
the de?ector plates 61b, 61c and 61d are so positioned
that progressively greater portions of the sand de?ected
from the targets are passed to the succeeding treating
stages.
In accordance with another aspect of the present inven 70
References Cited in the ?le of this patent '
UNITED STATES PATENTS
1,959,465
'Dryfoos ______________ __ May 22, 1934
2,223,018
2,813,318
Christensen __________ __ Nov. 26, 1940
Horth _______________ _._ NOV. 19, 1957
2,861,304
2,939,189
Wenninger ___________ __ Nov. 25, 1958
Wenninger ____________ __ June 7, 1960
433,034
Great Britain _________ _._ Aug. 7, 1935
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